The following are the
various billing models followed by Penguin Commercials.

Time and Materials
The standard time-and-materials method of work, based on Accruals.
This is
usually monitored through weekly timesheets and progress reports.Time and Materials with Not-to-Exceed clause
A standard time-and-materials method, with an additional clause that
price
will not exceed a certain amount.Fixed-price Project
Project bids, on fixed-price fixed-time basis. Bids may be fixed on
hard set of specifications, or accommodate certain level of flexibility.Milestone-based payment schedule
In a remote development project, milestones-based payment schedules
reinforce progress monitoring, and the evolution of firm, achievable
milestones. Milestone-based payment helps you justify payment, and
visible progress reduces risks.Monthly Resources-Based Payment
Schedule Ideal for the Extended Development Center model, billing
is done
monthly based on the number and level of resources utilized.